The present invention relates generally to the insertion of prewound coils and insulators in magnetic cores such as dynamoelectric machine stator cores. More particularly the present invention relates to a method and apparatus for placing coils and intermediate insulators in cores in which some coils are already positioned.
A number of machines have been devised for inserting prewound coils as well as, optionally, insulating wedges into statorcores. Illustrative of such machines are the Hill U.S. Pat. No. 3,324,536 and Walker et al, U.S. Pat. No. 3,402,462. Coil placing machines of this type typically include a plurality of generally parallel extending finger elements for supporting coils and a magnetic core into which the coils are to be placed along with a plurality of wedge guides adjacent portions of the finger elements for engaging the magnetic core. A stripper is reciprocable along finger elements to engage and move the coils into the magnetic core and insulating wedge push rods are reciprocable along the wedge guides to engage and force insulating wedges into the core slots radially inwardly of the coils.
While the placement of the insulating wedges which lie radially inwardly of the windings by the same machine which places those windings in the core slots is well established, the machine placement of so called phase insulators which function to separate one winding from another within the dynamoelectric machine stator is for several reasons substantially more difficult to achieve. Typically such phase insulators will include end turn insulating sheets joined by leg portions intended to lie in the core slots intermediate the windings. Such phase insulators may for example be disposed intermediate the main and start windings of a single phase induction motor or between the several phase windings of a polyphase motor. Patents illustrating various approaches to the machine insertion of phase insulators include Clark, U.S. Pat. No. 4,090,290; Urick et al, U.S. Pat. No. 4,276,689; and Miller et al, U.S. Pat. No. 4,335,325. These patented schemes have one or more of the following drawbacks: not being readily compatible with coil placing machines of the type illustrated in the above-referenced two patents or with more complex multiple process machines employing such coil placing devices as an integral part thereof; requiring a guide element to be positioned by the operator in the coil placer's tooling; requiring phase insulators having excessive leg length so that the end turn insulating portion of the phase insulator may be separated slightly from the stator at one or both ends thereof; requiring a separate phase insulator inserting step; the occasional tearing of an insulator; the occasional trapping of a portion of the insulator between the coil placing tooling and the stator core; the frequent failure of the leg portion of the phase insulator to adequately separate windings within a slot; and the inadequate reduction in overall dynamoelectric machine stator fabricating time.
Frequently, coil placing machines of the above-referenced type form a part only of a more complex coil winding and placing device as illustrated for example by U.S. Pat. Nos. 3,625,261 and 3,828,830 both to Hill et al as well as U.S. Pat. No. 4,455,743 issued June 26, 1984, in the name of Witwer, et al. While the first commerical embodiment of the present invention is presently contemplated as being part of a somewhat simplified version of the last mentioned Witwer, et al machine, the principles and techniques of the present invention are applicable to a wide variety of coil placing devices of the types referred to above as well as others. Reference may be had to any of the aforementioned patents for details of the machine operation generally.